Is he actually a yb?

[OhhWatALoser]

For my own edification, what are the markers you're looking for to identify the morph?

I don't know how to describe it really, but the pattern/flames on the side above the white belly is what to look for. The pattern on the snake, the yellow sides, and lighter dorsal are all typical of a yellow belly also, but that doesn't always hold true. There are low expression yellow bellies, but this one is pretty obvious.